People are familiar with the head of a spray gun. A wide variety of heads of different specifications are available. The head designed specifically for mounting on a spray gun is able to shoot out a spray of liquid (e.g., paint) contained in the spray gun to the surface of any object. The object thus can present a particular pattern on its surface. The head of a conventional spray gun is described in detail below.
Referring to FIGS. 1 and 2, the head 10 of the spray gun 1 comprises a flow distribution mechanism 11, a cap 12, and a ring 13. The flow distribution mechanism 11 is disposed forwardly of the spray gun 1. Pressurized air in the spray gun 1 is adapted to travel to the flow distribution mechanism 11. The flow distribution mechanism 11 comprises external threads 111, a central nozzle 112, a plurality of first apertures 113 equally spaced around a rear surface of the nozzle 112, an annular projection 115 around the nozzle 112 (see FIG. 2), a plurality of second apertures 116 equally spaced around a front surface of the nozzle 112 proximate the projection 115, a disc 117 on a front surface of the projection 115, the disc 117 having a diameter slightly smaller than that of the nozzle 112, a central mouth 118 disposed forwardly of the disc 117, the mouth 118 being an opening of a liquid (e.g., paint) channel in the spray gun 1, and a plurality of third apertures 119 equally spaced around an annular edge of the disc 117 distal to the mouth 118. In operation, pressurized air enters the flow distribution mechanism 11 of the spray gun 1 prior to exiting via the first apertures 113, the second apertures 116, and the third apertures 119 sequentially.
The cap 12 comprises a central orifice 121 and two pairs of holes 122 at two opposite sides of the orifice 121, the holes 122 of the same pair being spaced by a predetermined distance such that the mouth 118 is adapted to dispose in the orifice 121 when the cap 12 is put on the flow distribution mechanism 11 and a predetermined gap exists between rear of the cap 12 and the surface of the flow distribution mechanism 11 after mounting. The cap 12 further comprises two forward opposite yoke arms 123 spaced from both sides of the orifice 121, and two pairs of first openings 124 each on the yoke arm 123 and being in fluid communication with either second opening 125 within the cap 12 (see FIG. 2). Inner surface of the cap 12 is shaped as a staged one with different diameters so as to matingly engage with the flow distribution mechanism 11.
The ring 13 comprises inner threads 131 adapted to threadedly secure to outer threads 111 of the flow distribution mechanism 11 for mounting the ring 13 around the flow distribution mechanism 11 and closing the gap between the rear of the cap 12 and the flow distribution mechanism 11. In operation, pressurized air in the flow distribution mechanism 11 may exit the spray gun 1 by passing both a first path from the first apertures 113 to the first openings 124, a second path from the second apertures 116 to the orifice 121 via the third apertures 119, and a third path from the second apertures 116 to the holes 122 via the third apertures 119 respectively (see FIG. 2).
However, the prior head 10 of the spray gun 1 suffered from a disadvantage due to its construction. For example, pressure of air leaving any group of the orifice 121, the holes 122, and the first openings 124 is not the same as that of either one of the remaining two groups. As a result, poor atomization occurs when paint leaving the mouth 118 mixes with the air. Thus, the prior head 10 of the spray gun 1 is not satisfied.
Reasons of the disadvantage can be fully understood by referring to FIG. 2 specifically. For path from the first aperture 113 to the first opening 124 via the second opening 125, air leaving the first aperture 113 may impinge on edge of the second opening 125 irrespective of whether the first aperture 113 is aligned with the second opening 125 or not. As an end, pressure within the head 10 is not balanced.
Moreover, the above occurs in the path from the second aperture 116 to the orifice 121 or the hole 122 via the third aperture 119. In detail, air leaving the second aperture 116 may impinge on edge of the orifice 121 or the hole 122. Similarly, pressure within the head 10 is not balanced. Such poor atomization of the spray gun 1 caused by not streamline internal components thereof is thus required to improve in order to overcome the inadequacy of the prior art.
It is understood that spray gun market is very large and competitive. It is also understood that for a manufacturer of the trade quality product with advanced features is the key to win over other competitive ones. Thus, continuing improvements in the exploitation of spray gun head should be constantly sought by manufacturers of the trade.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.